Digital light processing three-dimensional printing with acrylic–titanium composite powders for multiscale porous scaffolds

Porous metals fabricated via three-dimensional (3D) printing have attracted extensive attention in many fields owing to their open pores and customization potential. However, dense internal structures produced by the powder bed fusion technique fails to meet the feature of porous materials in scenarios that demand large specific surface areas. Herein, we propose a strategy for 3D printing of titanium scaffolds featuring multiscale porous internal structures via powder modification and digital light processing (DLP). After modification, the titanium powders were composited with acrylic resin and maintained spherical shapes. Compared with the raw powder slurries, the modified powder slurries exhibited higher stability and preferable curing characteristics, and the depth sensitivity of the modified powder slurries with 45 vol% solid loading increased by approximately 72%. Green scaffolds were subsequently printed from the slurries with a solid loading reaching 45 vol% via DLP 3D printing. The scaffolds had macropores (pore diameters of approximately 1 mm) and internal open micropores (pore diameters of approximately 5.7–13.0 μm) after sintering. Additionally, these small-featured (approximately 320 μm) scaffolds retained sufficient compressive strength ((70.01 ± 3.53) MPa) even with high porosity (approximately 73.95%). This work can facilitate the fabrication of multiscale porous metal scaffolds with high solid loading slurries, offering potential for applications requiring high specific surface area ratios.